1. Field
Apparatuses and methods consistent with exemplary embodiments relate to constructing a map for a mobile robot to reduce a data amount and to increase an approach speed.
2. Description of the Related Art
A mobile robot should not only perceive a self-position in a given environment but should also construct a map of a surrounding environment when entering into a new environment that has not been previously explored. Constructing a map for a mobile robot involves a task of identifying a position of a nearby obstacle or object, an open space through which the mobile robot can freely move, and the like, and recording information obtained by the identification in an appropriate method.
Methods of constructing a map for a mobile robot may be largely classified into a two-dimensional (2D) grid-based environment map constructing method and a quadtree-based environment map constructing method. The grid-based environment map constructing method allows a robot to segment a surrounding environment into 2D grids and to record whether an obstacle exists in an arbitrary grid at a current position of the robot. However, the grid-based environment map constructing method has a problem in that a large memory capacity is required since a data amount increases as a traveling distance of a mobile robot increases or a size of a space to be moved increases. On the contrary, since the quadtree-based environment map constructing method assigns information to nodes by segmenting an area in which an obstacle exists into minute areas but displays only information on a node representing one large space for an area in which no obstacle exists, a memory can be efficiently used. However, since the quadtree-based environment map constructing method does not have space index information, a long approach time is required to approach an arbitrary node, and it is complicated to search for a position of stored data, and thus, the quadtree-based environment map constructing method is inappropriate for path planning.